Method of manufacturing an autosterile,silver impregnated,keratin containing article



United States Patent 3,536 442 METHOD OF MANUFACTURING AN AUTO- STERILE,SILVER IMPREGNATED, KERA- TIN CONTAINING ARTICLE Robert Brun, Geneva,Switzerland, assignor to Semi S.A., Geneva, Switzerland, a corporationof Switzerland No Drawing. Filed Jan. 26, 1967, Ser. No. 611,811 Claimspriority, application Switzerland, Feb. 1, 1966, 1,402/66 Int. Cl. D06m3/06, 3/08, 3/10 U.S. Cl. 8127.5 2 Claims ABSTRACT OF THE DISCLOSURE Anautosterile article having permanent bactericidal properties andcontaining a metal in the divided state, colloidal or ionic, such assilver, bismuth, copper or mercury.

A method for treating said article by immersion in a solution containingsaid metal.

It has already been proposed to confer bactericidal properties tovarious objects, in particular to tooth brushes and to fabrics adaptedto be employed as dressings.

However, up to the present it has not been possible to obtain a lastingbactericidal action, and the objects treated lost their bactericidalquality after relatively short use.

The invention has for object an autosterile article, characterized inthat it contains or carries a metal in a divided state, colloidal orionic, preventing the development of bacteria, fungoid growths andmildew and rendering the article autosterile and autodeodorized.

The invention also relates to a method for the production of thisarticle, characterized in that one treats the article by immersion in asolution containing said agent.

The articles may be composed of various materials, for example naturalor synthetic fibres or hairs, plastic materials, natural or syntheticleather, paper, rubber, ceramics, wood, metals or other substances ofanimal, vegetable, mineral or synthetic origin.

The articles to which this method may be applied are all those which, ina direct or indirect manner, may enter into contact with man or animal,for example hair brushes, tooth brushes, nail brushes, beard brushes,gloves and toilet linen, natural or synthetic sponges, clothing,underclothing, or parts thereof, handkerchiefs, articles for privatehygiene, or dressings, stockings, socks, linings or inner soles ofshoes, articles serving for packing or adapted to contain food, cosmeticor pharmaceutical products, a

and all articles and instruments adapted to be in contact temporarily orpermanently with the skin or with the mucous membranes of man or animal.

The agent may be included in the material which will serve for themanufacture of the article or fixed afterwards, according as to whetherthe material employed will be synthetic or natural.

This agent is a metal in the divided state, colloidal or ionic, whichhas anti-microbic properties and must be fixed in such a manner that itremains or becomes prac tically insoluble, whatever be its definitivechemical or physical structure. The metal may be, for example, silver,bismuth, copper, mercury, etc.

The fixation of the metallic ions is effected, preferably, by immersionin a solution of salts of these metals, then by transformation intometallic oxide or hydroxide and reduction to a finely divided metal by achemical or physico-chemical process. When the agent must beincorporated in a synthetic material, it may be incorporated directly inthe form of the finely divided metal (precipitated or colloidal).

In order to allow of better penetration or to cause to appear reactivechemical or physical functions in the 3,536,442 Patented Oct. '27, 1970material constituting the article, such as the hairs of a brush forexample, they may be subjected to a pretreatment, for example byimmersing them in solutions of ammonium thioglycolate, sodiumlaurylsulphate, sodium sulphide, tannin, chromium or aluminum salts,etc.

In the case of the action of ammoniacal silver nitrate on the keratin ofthe hair, it is established that there is not only absorption of thesilver salt, but fixation of this metal and formation of an insolublenew compound which has been called silver keratinate. Silver ion fixeson electronegative groups, that is, for example, the sulphydrile andcarboxylic functions of keratin, then when these functions aresaturated, it is absorbed.

Thus, when 1 gr. of hairs is placed in contact, during 24 hours, with asolution containing about mg. of silver nitrate (in the form of theammoniacal complex), all the silver ions are fixed and there do notremain any in the solution. When this critical point has been reached,one observes an absorption in equilibrium with the silver ionconcentration of the solution.

Examples for carrying out the method according to the invention:

EXAMPLE I Treatment of brush hairs 100 gr. of hairs are immersed in 1litre of an aqueous solution of sodium laurylsulphate at 10% during onehour at the temperature of 50 C., then in 1 litre of a solution ofsilver nitrate at 2% at the temperature of 20 C. One removes the air bypassing under reduced pressure during one minute. The hairs are left inthe silver nitrate solution for 24 hours while slightly stirring thesolution, then the hairs are treated by 1 litre of caustic soda n/ 10for 5 minutes, and then by 1 litre of formaldehyde in solution at 2.5%for 1 hour. The hairs are then washed with running water accompanied byvery strong stirring until elimination of the particles which do notstrongly adhere to the hairs.

EXAMPLE II Treatment of brush hairs 100 gr. of hairs are immersed atordinary temperature in 2.5 litres of the following solution: 10 gr. ofsilver nitrate, 22 gr. of ammonium hydroxide (15% NH;,), 968 gr. ofdistilled water. The included air is removed by rapid passing at reducedpressure and the hairs left in the solution for 24 hours While slightlystirring. The hairs are then treated with 2.5 litres of caustic sodan/10 for 5 minutes, then with 2.5 litres of formaldehyde in solution at2.5% for one hour. The hairs are then Washed with running water withvery strong stirring until elimination of the particles which do notstrongly adhere to the hairs.

Whereas in Example I, the hairs have been subjected to pretreatment in afirst solution, a single treatment is applied thereto in Example II.

EXAMPLE III Treatment of a cotton fabric The fabric is immersed in asufficient quantity of an aqueous solution of silver nitrate at 2%containing 0.2% of a non ionic surface active agent, then wrung anddried. It is then immersed in an aqueous solution containing 0.3 ofhydrogen peroxide and 4% of caustic soda, and left for 15 minutes inthis bath.

I claim: A

1. A method of manufacturing an autosterile keratin containing articlein which silver is made to penetrate the keratin so as to prevent theformation of bacteria on said article and thereby render the articleautosterile which method comprises:

first immersing said article into a heated solution containing sodiumlaurylsulfate;

thereafter immersing said keratin containing article in a solutioncontaining a soluble salt of silver; then, after the second immersion,transforming the metal on said article into a metallic hydroxide by theaction of an alkali solution thereon; and subsequently reducing thehydroxide to metal by the action of formaldehyde so as to obtain ametallic silver dispersion through the substance of the article. 2. Amethod of manufacturing an autosterile keratin containing article inwhich silver is made to penetrate the keratin to be made autosterile,comprising:

first immersing said article into a heated solution containing sodiumlaurylsulfate; thereafter immersing said article in a solutioncontaining a soluble salt of silver; then, after the second immersion,transforming the metal on said article into a metallic oxide by theaction of an alkali solution thereof; and

subsequently reducing the oxide to metal by the action of formaldehydeso as to obtain a metallic silver dispersion through the substance ofthe article.

References Cited UNITED STATES PATENTS 2,304,478 12/1942 Rosenzweig8127.5 2,459,896 1/1949 Schwarz 1l7138.5 3,380,848 4/1968 Horowitz117l38.5 XR

GEORGE F. LESMES, Primary Examiner J. R. MILLER, Assistant Examiner US.Cl. X.R.

